Platform setup via DTS

[Anton D. Kachalov <mouse@yandex-team.ru>]

I would like to start a little discussion around board setup process in arch/arm/mach-aspeed/aspeed.c.
For most cases this process is "flat": just modifying regs one-by-one. Sometimes with applying mask.
I have an idea to add an array of "instructions" to the Device Tree in the following manner
(I hope dtc's preprocess via cpp resolve ORed macro in the correct way):

==========
#include <dt-bindings/soc/aspeed.h>

/ {
    model = "Our HW";
    compatible = "aspeed,ast2400";
    board-setup = <WR, AST_BASE_LPC | 0x9c, 0x02010023, 0>,
                           <WR, AST_BASE_SCU, SCU_PASSWORD, 0>,
                           <WR, AST_BASE_SCU | 0x80, 0xcb000000, 0>,
                           ...
                            /* write(read() | 0x1000) */
                           <OR, AST_BASE_SCU | 0x2c, 0x00001000, 0>,

                           /* write((read() &~ 0x2000) | 0x1000) */
                           <OR, AST_BASE_SCU | 0x2c, 0x00001000, 0x2000>;
==========

or in less talkative way:

==========
                            /* write((read() &~ 0) | 0xcb000000) */
                           <AST_BASE_SCU | 0x80, 0xcb000000, 0>,
                           ...
                            /* write((read() &~ 0x1000) | 0x1000) */
                           <AST_BASE_SCU | 0x2c, 0x00001000, 0x1000>,
==========

to completely eliminate board-specific init functions.


-- 
Anton D. Kachalov